Rotary drum drier



18.1.29,1935. R. @woon 1,989,255

ROTARY DRUM DBIER Filed Nov. 5,11930 asneetS-sheet. 1

Jan. 29, 1935.` R. o. wooD 1,989,255

` n 'RQTARYD'RUM DRIER 4` Filed Nov. 3, 1930 2 sheets-shea 2 Patented `an. 29, 1935 Y UNITED fsTA'rEs: orsi-ce; l

, ROIABYDRUM DRIRE l Robert 0Ly Wood, Hamburg,l Y., 'assigner to National Anilne'and'ChemicaI Company, Inc@ Newfriforh'xNv. facon-poration of y l. Aa.praattenrivente.,19rd;strahlen'21913334f 'ilrolaima (G1. 15e-ral This invention relates .to rotary drum driersor angle of repose; Agledge orv shelf preferably. evaporators- 'of the. interiorlyfheated type, and provided adjacent the-edgeA of they doctor which; comprises certain'improvements inconstruction. is spaced. from, the roll andfrom the doctor and and design as will hereinafter be pointedout.` Y uponwhichA will lhe pushed `the powdered lmate- 51 As .ordinarily constructed .thesedriers `comrial as-itaccumulates 4on the, roll near the doctor,l 5 prise two horizontal smooth faced rolls or drums, therebylincreasing.theoaccumulation of material slightly separated at their peripheries andd-isarourrdthe edge of.r thelldoctor... From this ledge-` posed onparallel axes, which .revolve inversely,v the powderedmaterialzis, pushed by accumulation.. the drums` or cylinders ,being interiorly heated by of `material. thereon downalong an inc'linewh'ichl 1Q; a suitable iiuid such asv steam, heated oil,[etc.y is graded to preventdusting, and intofac'ontainer. 1:0 The liquid to be evaporated is introduced between suitably closed` topreuentdusting and access of the vrollsfancl is. prevented from flowing away bysteam andgvapor thereto.. In the preferred em suitable retainingmeans. As the rolls revolve, bodiinent of the im(mention. retainersy bear. against their .surfaces collect the liquid in a'thin filmvv the facesyof the drums .'to" hold'liqu'id within the 1:51: which dries on the rolls almost immediately'due, confines ofthe drumsfandlform-narrow -fstrip-` 15 tothe high temperature at which the rolls are like areas on thesurfacefof the drumswhich are. maintained. This lm is then'scraped off of theV free fromfplm andprovide.bearingsurfaces forj rolls in the course of their revolution by a knife or the ledge and `vl'i'o'pper support.:l

doctor. y n A For a more detailed description`of .the...inven 2.9L. Generally',I in lworking with `solids which are tion referencegis 'madeto .the accomplanyingl 2Q somewhat coherent,- the: film is scraped oiin drawings showinga. preferred'efmbodiment 4of the flakes or sheets. lBut in evaporating certain subinventionand. wherein .Figure lisa view partlyjirr stances which haveza tendency to dust, as for. vertical section; Figure 2 is a7V section .taken on" example, dyestuffs or certain food products, line 2-2 *of Figure-1 ;1'igure` 3 f isan lend view 25 which have a somewhat brittle consistency, thev partly in. section; blig'ureui isa fragmentary view 2.5 doctor.- remove's-thelm in fine particlessome ofA of the doctor.,` roll. and'fhopperrFigure 54 is a which are discharged into the air at a considfragmentaryVioW-.oithe dC' and-Supprtl'nd erable'v'elocity. In addition to' the vloss of ma- Figure 6 isan elevation of .the-hopper.

terial thuslentailed, these particles,-especia1ly if The numerals 1I and 2,.Y ydesignate two drying g they form an obnoxious dust, such as is produced drumslwhich areY arrangedgon. parallel axes and 30`v by dyestuffs, produce unhealthful working leoncontact at their outer surfaces. The drums are ditions. `This condition can not be remedied by supported-on hollow trunnions 3.,'y 5 -1and 4, 6," refl enclosing the drying rolls in a casing, forthen spectively. The-drumsl and`2are`.er1closedwithy the escaping water vapor formed in the evaporain aoasing il, which hasan 'opening 8v in 'one end.A

3 5, tion moistens the particles removed from the .-rolls thereof through which the rolls` may .beremoved 35 and produces an incompletely dried product, for replacement or ripainf.4 During operation, ,the

According to one feature ofthe present inven-V openingpa is closed by a side plate il which' is tion,.the doctor Vor scraper yacts at a position ony held in position against the side ofthe casing by the upwardly moving surface of the roll sufficientstudsA 1 0 threadedfinto the casingv wall. A7 gasket 40 ly elevated above the axis of 'the roll so that the interposed between'theside plate 9 and'side of the 40* surface or tangent at the point ofcontact of thev casing forms a' liquid tight joint. vThe side plate doctor withthe roll makes an angle with the 9 hasanopeningI- ll and anelongated. opening 12 horizontal which is substantiallyequal to or less therein in which'aresupported the bearing plates thanl thek angle o f reposeof the material being 13 and14. On the opposite side the casing 7 has 45.. treated. Consequently; the material which is an opening 15 and anv elongated opening 16 in 45 scraped off of the roll, will accumulate'on the surwhich 4are supported the vrbearing :plates 17 and. face of the roll adjacent the edge of the `doctor 18. Thetrunhions 3,124,5and'6 are .journalledin and will dampen or completely suppress the tendthe bearings 19,-carriedin the bearing plates 13', ency of the fresh particles to be expelled into the 14 L7 and 18. To prevent liquid lfrom escaping 50j air. The accumulation of material ongthesurface from. the casing, the bearingplates 13,14, 41'7 and 59 of the roll adjacent the edge of the doctor will 18 haverecess'es-20vtherein toreceive the packe.

be 'assistedby the direction; of rotation of the ing2l. vPacking glands'zlare slideably secured roll, which is upward at that position and conseover the trunnions 3, 5, i and 64 tocompress the quently produces anfapparent angle of repose at; packing 2-1 in thevrecesses 20.

that point. greater than the actual, oit-'absolute Steam supplied tothe drumsland 23, and steam passes from the drums through the exit pipes 24. Since the construction of both drums 1 and 2 is identical only one need be described in detail. The trunnions 4 and 6 are eX- teriorly threaded at their outer ends as indicated at 25. Packing nuts 26 are threaded on the ends of the trunnions and compress the packing 27 between the interior Walls of-fthe hollow trunnions and the steam'pipes 23iand.""24,y respectively, to provide steaml tight joints.

The drum 1 is rotated by a worm driven by suitable means and coacting with the `wforrn,gear

28 secured to the trunnion 5. A gear'29 ori theV trunnion 3 coacts with the-gear 30k-ontrunnion 4 to rotate drum 2 and drum lin opposingfdi-- by the adjusting rods 31 which bear against the bearing plates 14 and 18, and may be set at the desired spacing bylocking the adjusting rods 31 to the adjustmentvrod support l Knife blades or` doctors' 33 vare adjustably'hel against the rollers 1` and` `2 'on supports'34. Since both knives and supports are'ofthefsame construction only joue-'need bedescribed in detail. The supportsi34 consistI of ai pair 'of vspacedside arms 35 and 36 suitably pivotedatl their ends on a supporting rod-37 which is journalled in the casing 7.l Theother-ends arejoined by a knife adjusting plate v33 having'a downwardlyproject-v in g .bar 39 inlwliich are'seated'the'knife adjusting screws 40. 'I 'he cap screws 4l and 42 clamp y the knife adjusting `pls`ite`33U to the spaced side arms 35 and 36; "I'hedoctor"y 33 is--slotted atf43 and is clamped tothefkni'feadjusting 'p1atev38 by cap screws A44 passing A through jthefslots 43 and threaded into the knife adjusting platea The knife supports 34'are1held-against "piv'oted *displacement by a stopbar 45 in which'f'ar'e set the adjusting screws 46 'which' bear lagainst y the side; arms 35 and V36 'to uadjust jthejpressure of the knife on the drum; Y, A

' 'Ihe screws f 41 have'a 'i shoulder 47 -thereon which serves as a pivotal'V support 'forfthe hopper or bin 48. The hopper"48 cmprises'two end plates 49 and 50 of generally arcuate-shape,

which are covered by a' sheet metal covering 51l and which at their upper'endareslotted at 52 K terial thereon to pass to form a hook which fits underthe shoulders 47 of the bolts 41. 'I'he 'end plates 49and 50 have shoulders v54 formed on their loweredgesto form a bearing which restsagainstthe drum near its` per. The hopper is held in' place by Vits own weight. h plates 49 and 50, the edge 55' of which suiii` cientlyv clears the drum to permit the-nlm of maunde'rneath thevedge without being scraped. f

In operation material to bef` dried is supplied between the drumsl and' 2, `as by supply-pipe 57 and is retained from ow'ingjover'th'e ends ofV the drums by the retaining blocks 56. Steam is supplied to the interior of the drums through pipes 23, forheating the drums'. 'Spent steam is discharged from thel drumsfthrough pipes 24. The drumsA are' rotated in the Vdirection ofthe arrows, Figure 3. Thedrums pickup aisheet or lm of lquidas theyp'ass through' "the liquid, which is quickly dried; by'the'heated'surface of the drums. The retaining blocks 56 vare shown as bearing againstthe facesof the drums, and consequently they will form'fnarrow strip like areas at the edges of the drums`-which ar'effree Av ledge 55` extends between the end from dried film. The rotation of the drum carries the film around under the edge 55 till it Vreaches the knife 33 where it is scraped off as ,particles from darting or spraying from the edge of the knife as they are separated from the surface of the drum. When suiiicient material accumulates on the ledge 55 the further accumulav-tion of material thereon pushes off the accumulated material which slides down the lower wall of theA hopper into ythe hopper. There is little or no dusting in this operation. The shoulders 54 on the end plates 49 and 50 bear on the clear strips atlthe edges ofthe drums so that the edge 55 can be adjustedk to clear the'lm'of Adried material on the drum. 'Iliehopper 48 .is closed by a cover 48.

'I'he knife 33 is supported by the bar or rod 37 so that vthe thrust which the knife edge receives'is almostinline with .the knife edge and supporting bar 37. Theknife can'be adjusted to exert the required pressure on the drum by turning vthe set screws 46 in orout of the bar 45.

It will be' obvious thatl changes in the construction shown in the accompanying drawings can be made without departing'from the scope of the `invention as defined inthe appended claims. M w.

lHaving described` my .-invention what I claim as new and desire to protect by Letters Patent is:

1.' In-'an apparatus of the character described,` the combination comprising an upwardly moving inclined heated surface, means for supplying material to be driedin the form of 'ai-11m on said surface, a doctor positioned above the surface and incontact therewith to. remove the film therefrom in the form of 'a powder, the position of the doctor Aand the surface being such that at'theline of contact of the surface and doctor the'surfaceV forms an anglewith the horizontal less than -the angle of repose of the powder, and a shelf adjacent the said surface and. doctor, positioned below said line of contact for receiving excess accumulation of powder. from the surface thereby assisting in covering the edge of said doctor.

2. `In a' rotary drumvv drier the combination comprising an internally heated drum, means for supplying liquid material to the drumto be dried in-alm on its outer surface, a doctor positioned above the surface and in contact therewith for removing dried material therefrom in the'form of a powder, the relative'position of the doctor and the drum beingsuch'that the tangent to the surface of the drum at theline of contact of the doctor and drum forms an Yangle with the horizontal less than the angle' offrepose of the powder, a shelf spaced from the'drum and adjacent the edge ofthe doctor for receiving the excess of powder which' accumulates on the roll, and means separating said doctor and the material removed thereby from the atmosphere surrounding said drum. A 3. In -a rotary drum drier the combination comprising an internally heated drum,'means for applying liquid material to the drum to be dried inthe form of a film thereon, retainers bearing against-the surface of the drum near its edges-v 4. In a rotary drum drier the combination comprising an internally heated drum, means for applying lit-uidv material to the drum to be dried in the form of a film thereon, retainers bearing against the surface of the drum near its edges for holding the liquid material within the confines of the drum, said retainers forming clear strips on the surface of the drum, a doctor positioned in contact with the drum for removing dried material therefrom, a pair of end plates mounted on said doctor' and having bearings formed thereon which rest on the clear strips, and a shelf supported by said end plates to receive the dried powdered material.

5. In a rotary drum drier the combination comprising a rotatable heated drum, means for supplying liquid material to the drum to be dried in the form of a film thereon, a doctor positioned in contact with the drum and having an edge for removing dried material from the drum, a hopper having an edge formed to provide an outer shelf for receiving dried material removed from the drum, and means for mounting said hopper with the shelf adjacent the edge of the doctor but spaced from the drum, whereby dried material removed from the drum is retained so as to cover said edge of the doctor.

6. In a rotary drum drier the combination comprising a rotatable heated drum, means for supplying liquid material to the drum to be dried in the form of a film thereon, a doctor positioned above the surface and in contact therewith for removing the film therefrom in the form of a powder, the position of the doctor and drum being such that the tangent to the surface of the drum at the line of con'tact of the doctor and drum forms an angle with the horizontal less than the angle of repose of the dried powdered material, and a ledge spaced from the drum and mounted adjacent the edge of the doctor for receiving the powder, said ledge having bearings resting on said drum.

'1. In a rotary drum drier the combination comprising a rotatable heated drum, means for supplying liquid material to the drum to be dried in the form of a film thereon, a pivotally mounted knife support, a knife in said knife support for removing the lm from the drum, a plurality of shoulders projecting laterally from said knife support, a plurality of end plates having bearing shoulders formed thereon for resting on said drum and having their upper ends hooked under said rst mentioned shoulders to form a cantilever support therefor, and a shelf supported by said end plates adjacent the edge of the knife.

8. In a rotary drum drier the combination comprising a rotatable heated drum, means for supplying liquid material to the drum to be dried in the form of a lm thereon, a pivotally mounted knife support, a knife adjustably mounted in said support for removing the lm from the roll, a plurality of shoulders projecting from said knife support, a plurality of end plates having bearing shoulders formed thereon for resting on said drum and having their upper ends retained under said -rst mentioned shoulders, and a ledge adjacent the edge of the knife supported by said end plates in spaced relation to Hsaid "drinn for accumulating dried material atthe'edge'of the knife.

9, In an apparatus`v of the character described the combination comprising a rotatablev heated drum, means for supplying liquid material to the drumto form a lm thereon, a pivotally mounted knife support, a knife adjustably mounted in said support forzremovingthelm 'from the drum in the formof. a powder,l a plurality of. shoulders projecting from said knife support, a plurality of members :having bearingshoulders thereon for bearing on said drum and having their upper ends retained by said rst mentioned shoulders to form a cantilever support therefor, a ledge mounted on said members spaced from said drum and adjacent said knife edge, and a closed hopper supported by said members for receiving material from said ledge.

Y 10. Apparatus for drying materials comprising a heated rotatable drum, means for applying ma terial to be dried to said drum, a doctor for removing dried material frorn said drum, and a container for receiving Amaterial removed from said drum, separatingsaid doctor and said material removed from said drum from the atmosphere surrounding said drum.

1l. Apparatus for drying materials comprising a heated rotatable drum, means for applying material to be dried to said drum, a doctor for removing dried material from said drum, and a container for receiving material removed from said drum by said doctor, said container being substantially closed to the atmosphere about said drum.

12. In a rotary drum drier, the combination comprising an internally heated rotating drum, means for supplying liquid material to the drum to be dried in a lm on its outer surface, retainers bearing against the surface of the drum near its edges for holding the liquid material within the confines of the drum, said retainers forming clear strips on the surface of the drum, a doctor positioned above the drum and in contact therewith fo-r removing dried material therefrom in the form of a powder, the position of the doctor being such that the tangent tothe surface of the drum at the line of contact of the doctor and the drum forms an angle with the horizontal less than the angle of repose of the powder, and a closed hopper for receiving powder from said doctor, said doctor comprising a pivotally mounted knife support, a knife adjustably mounted in said support, and a plurality of shoulders projecting from said knife support, and said hopper comprising side members mounted on said shoulders, and having projecting bearing surfaces for resting on said clear strips, and a ledge adapted to receive powder from said knife and retain it in contact with the edge of the knife.

13. In an apparatus of the character described, the combination comprisingan upwardly moving inclined surface, means for supplying material to form a film on said surface, a doctor for removing the film from said surface in the form of a powder, said surface in the course of its upward movement passing through a position where it forms an angle with the horizontal less than the angle of repose of the powder, and means for mounting said doctor above said surface and in a plane which forms an angle with the horizontal greater than the angle of repose of the powder, the location of the doctor being such that it contacts said surface while the latter is in said position, whereby powder removed by the doctor is drum at the lIne* of contactoflthe doctor; and; the: drum forms an angle With the horizontal less than the angle of repose of the powder, and meansfor; mounting said doctor .inr said gposition'; and-1111; `at: plane which forms an angle;V with` rthehorizontal; greater than-the angle of repose ofothe powder; whereby Vpowder :removed bythe doctor is :dis-- charged downward over the edge of thedoctor.

Aand rests on said upwardly-moving surfacefbelow 

